A chimney insulating element

Abstract

 A chimney insulating element of mineral wool, for a three-layered chimney comprising an inner pipe (2), the insulating element (3) and a casing (1), forms a polygon at least with its outside contour.

Description

[0001] This invention relates to a chimney insulating element according to the preamble of claim 1.

[0002] Chimneys or smokestacks are usually provided with thermal insulation between inner pipe and casing to protect the casing from excessive heating, on the one hand, and ensure a good draft of the chimney, on the other hand, and furthermore to avoid fast cooling of the smoke pipe in the interests of low condensate formation. It is known to use insulating elements of mineral wool which are adapted in contour to the circumference of the inner pipe. For example it is known from AT-PS 346 554 to provide insulation boards of mineral wool at predetermined intervals with cavities which are for example introduced into the insulation board from outside by mechanical processing to permit the insulation board to be bent into a tubular insulating element in accordance with the tubular inside contour of the casing and the tubular outside contour of the inner pipe. Instead of introducing cavities into the insulation boards, it is further known (DE-OS 37 05 725) to produce the chimney insulating element by pleating or folding a crude mat of predetermined thickness, selecting the depth of fold according to the particular desired radial dimension in conformity with the encased inner pipe. However, these contour-adapted, in particular circular, insulating elements are disadvantageous in that comparatively high frictional forces occur between the insulating element, on the one hand, and the inner surface of the casing and the outside surface of the inner pipe, on the other, when the insulating element is introduced, so that it is difficult and awkward and thus very time-consuming to insert the insulating element into the space existing between inner pipe and casing.

[0003] The problem of the invention is to provide an easily produced chimney insulating element which can be transported cost-effectively and mounted easily and in secure position.
This problem is solved according to the invention by the features contained in the characterizing part of claim 1, expedient developments being characterized by the features contained in the subclaims.

[0004] The chimney insulating element is formed according to the invention as a polygon at least on the outside, i.e. on its outside surface facing the casing. The insulating element therefore not only limits rear ventilation cavities with the opposite casing, but its circumference is only in areal contact limited to certain areas with the casing so that it is easier to introduce the insulating element between casing and inner pipe due to the low frictional forces. If, in especially advantageous fashion, the inside contour of the chimney insulating element is at the same time also formed as a polygon in accordance with the outside contour, the resulting contact area with a usually circular inner pipe is only linear, which greatly reduces the frictional resistance and thus facilitates introduction of the insulating element into the space between inner pipe and casing. At the same time such a polygonal contour on the inside causes rear ventilation cavities to be formed between insulating element and preferably circular inner pipe, so that when the smoke pipe is greatly heated the air in the cavities is also heated permitting heat to be removed upward over the roof. This also allows the use of insulating elements which are otherwise advantageous but not very temperature-stable, since the heat removal taking place between insulating layer and smoke pipe reduces the temperature stress on the insulating material even at a soot burning temperature of approx. 1000



C. If ventilation of the cavities is undesirable, it can easily be prevented by mounting a lid or any other upper cover. The merely linear contact with the inner pipe also results in a lower heat load on the insulating layer compared to areal contact between insulating element and inner pipe.
The insulating element system is preferably formed as an octagon with circular smoke pipes and as a square with rectangular or square inner pipes, although other polygonal forms, in particular pentagons, hexagons or heptagons, can also be expedient.

[0005] Shifted or twisted installation of the insulating element is excluded in advantageous fashion if the length across the corners of the insulating element is greater than the clear width of the casing. This also reliably avoids installation errors with the joint in the rear ventilation area, regardless of whether the insulating element exists in one piece or is formed from several boards. It also reliably prevents the insulating elements from yielding into the rear ventilation areas.

[0006] A further advantage is the exact positioning of a polygon within a space between casing and inner pipe, whereby a force-locking seat can be obtained with the element lying against the inner pipe and the casing. If one realizes a circumferential hollow channel, a so-called annular gap, between insulating element and casing it is possible to fasten the element to the smoke pipe in simple fashion via strong surface material and mechanical fastening means. These mechanical fastening means are unnecessary if the outside contours of the insulating elements and the inside contours of the casing bricks are coordinated with each another in such a way as to prevent the insulating elements from yielding in the installed state. Instead of using casing bricks formed accordingly on the inside, it is also possible to introduce aids between misfitting casing bricks and insulating elements, such as profile strips equipped with receiving or holding faces which are V-shaped and thus adapted to the corner areas of the insulating element, which achieve the same effect.

[0007] In especially advantageous fashion the chimney insulating elements consisting of insulation boards are obtained by folding the same, because they are provided parallel to their longitudinal axis with groovelike recesses, e.g. with a V-shaped cross section, the grooves being formed, and/or the intervals between the grooves selected, in such a way that the desired polygons are obtained when the boards are folded, the ends of a board meeting to form the polygon. The joint is preferably located in the corner area of the polygonal insulating element in the installed state. The surface of the insulation boards opposite the grooves is expediently lined, preferably with glass mat or with another strong surface material, such as glass fabric, glass laminate or thread-reinforced glass mat, so that mechanical fastening means can engage it accordingly. This permits the chimney insulating elements designed as polygonal elements to be stored and transported very easily, since it is easy to fold them out of their flat initial state for transport and storage into chimney insulating elements on the spot. The invention thus provides polygonal chimney elements starting out from a board form.

[0008] In the following some embodiments of the invention will be described with reference to the drawings, in which:

Fig. 1

shows a sectional view of a chimney insulated according to the invention,

Fig. 2

shows a sectional view of a further embodiment corresponding to Fig. 1,

Fig. 3

shows a sectional view of a further embodiment corresponding to Fig. 1,

Fig. 4

shows a side view of an insulation board in the initial state out of which chimney insulating elements are folded,

Fig. 5

shows a sectional view of a further embodiment,

Figs. 6 and 7

show views of further embodiments of insulation boards in the initial state before being folded into polygonal chimney insulating elements, and

Fig. 8

shows a sectional view of a further variant corresponding to Fig. 1.

[0009] The chimney shown in Fig. 1 is formed from prefabricated casing 1 in the manner of a casing brick made e.g. of lightweight concrete with a square cross section here, flue gas-carrying inner pipe 2 made e.g. of ceramic material, and insulating element 3 of mineral wool disposed therebetween, whereby it need not be explained here that casing bricks 1 and inner pipes 2 are stacked in layers as prefabricated elements to form the chimney and the insulating elements accordingly disposed therebetween.

[0010] The chimney element shown in Fig. 1 is made of mineral wool, starting out from an insulation board shown schematically in Fig. 6 and described more closely in the following. Chimney insulating element 3 has a corresponding polygonal contour on the outside and inside, the contour of an octagon here. In the shown embodiment the length of insulating element 3 measured across opposite corners is greater than the clear width of inside casing 1, so that the insulating element is positioned exactly within a space between circular inner pipe 2 and casing 1. Shifted or twisted installation is impossible. Insulating element 3 is seated firmly within the space, the inner boundary being in approximately linear contact with inner pipe 2 at 4, and the outside of insulating element 3 being in areal contact with casing 1 at 5. Due to its polygonal contour, insulating element 3 limits channel-like rear ventilation cavities 6 with casing 1, on the one hand, and channel-like cavities 7 with inner pipe 2 which is circular here, on the other hand, which can be used for rear ventilation if necessary. When the chimney is heated due to firing, an air circulation can arise within cavities 7 so that heat is removed upward thereby reducing the temperature stress on the insulating element. This makes it possible for less temperature-stable insulating materials to meet the required specifications for acceptance, e.g. with a soot burning test at 1000

C for house chimneys. If ventilation of internal cavities 7 is undesirable for example, one can prevent the air circulation by mounting an upper cover in the manner of a lid. The linear contact of insulating element 3 with inner pipe 2 at 4 reduces the direct temperature load on the insulating layer likewise coming from the smoke pipe, which in turn, in conjunction with preceding cavities 7, leads to lower heat stress on insulating elements 3. The linear contact surface results in reduced frictional resistance upon assembly of insulating elements 3 or the smoke pipes. In particular, the air current within rear ventilation cavities 7 is dependent on the gap width and temperature difference. For example at a temperature difference of approx. 50 K, normal air pressure of 105 Pa and a gap width of about 0.1 m an air flow will arise, whereas e.g. at 200 K turbulent flow is to be expected. In low temperature heating systems, however, where there is no convection, i.e. "airing", at all e.g. at temperature differences of approx. 20 K if the gap width is under 0.01 m, the "steady air cushions" in rear ventilation cavities 7 can be considered insulation supplementing the linear contact of insulating elements 3.

[0011] In the shown embodiment the insulating element is formed from a board-shaped initial element according to Fig. 6 by making the ends of the board meet. However insulating element 3 can also be formed from two or more boards which are set together along the circumference in abutting relationship. Since the board or boards abut in the area of the corners of the polygon, the insulating products cannot yield into the rear ventilation areas. Installation errors with joints in the rear ventilation area are also reliably avoided since, as described above, the diagonally measured greater length of the insulating element compared to the clear width of the casing bricks makes shifted or twisted installation impossible.

[0012] In the embodiment of Fig. 2 octagonal insulating element 3 is again disposed between casing 1 and circular inner pipe 2. Insulating element 3 is lined on the outside surface facing the casing with a strong surface material, e.g. glass fabric or glass laminate, so that insulating element 3 can be fastened to the smoke pipe via the surface material and mechanical fastening means 8. In the shown embodiment, mechanical fastening means 8 consist of steel springs or clamps. Rear ventilation cavities 7 are also present between insulating element 3 and inner pipe 2 in the embodiment of Fig. 2, outer rear ventilation cavities 6 now being formed as a ring channel running all around the circumference.

[0013] Fig. 3 shows square insulating element 3 adapted on its inside to the outer contour of inner pipe 2 which is rectangular or square here. Rear ventilation cavities are provided here only between insulating element 3 and casing 1, being formed again as a ring channel running all around. Insulating element 3 is fastened to smoke pipe 2 again here via strong surface material and mechanical fastening means 8.
Figs. 4 and 6 show chimney insulating elements in their flat form, as supplied, in the manner of an elongate board, the boards being folded for use as insulating elements into polygonal insulating element 3 shown in Figs. 1 to 3. For this purpose the insulation boards of Fig. 4 and 6 have V-shaped grooves 10 at adapted intervals extending perpendicular to the longitudinal extension of the boards and in particular set with respect to their angle in such a way that one obtains the desired polygons by folding the individual surface areas along grooves 10. On the surface opposite grooves 10 the insulating elements are expediently provided with a lining of glass mat or another strong surface material, whereby stronger surface material is used in particular in embodiments according to Figs. 2 and 3 and the glass mat in embodiments according to Figs. 1 and 5 where the insulating elements are received in the space between inner pipe 2 and casing 1 with a force-locking seat. The lining is illustrated at 11. However it is also conceivable to omit the lining, i.e. do without it, if the insulating material is sufficiently strong. The lower portion of the insulation board shown in perspective in Fig. 4 has, as an alternative, rear ventilation cavities 7 which not only provide ventilation between inner pipe 2 and insulating element 3 but also advantageously compensate thickness tolerances and reduce the friction.

[0014] In the embodiment of Fig. 5 insulating element 3 is formed as a polygon, an octagon here, only with respect to its outside contour, and held by fastening blocks 8 formed integrally with the casing here and having V-shaped receiving surface 9 adapted to the corners of the insulating element. The inside contour of insulating element 3 is adapted to the circular contour of inner pipe 2 according to Fig. 5 so that cavities 6 for rear ventilation are formed only between the outside contour of the insulating element and the casing. In a further especially expedient embodiment, insulating element 3 is also provided with a corresponding polygonal contour, an octagon here, on the inside, thereby again forming rear ventilation channels. To form the insulating element of Fig. 5 it is suitable to use in particular the insulation board shown in Fig. 7, which is again provided as in Figs. 4 and 6 with grooves 10 and between grooves 10 with curved recesses 12 so as to guarantee the hitherto desired close fit of the inside contour of insulating element 3 with the outer contour of inner pipe 2. In the embodiment of an insulation board in Fig. 6, in use in Fig. 5, it is guaranteed that one obtains an octagonal inside contour and thus possible rear-ventilated areas between insulating element 3 and inner pipe 2.

[0015] Fastening blocks 8 with which receiving surfaces 9 are formed can be part of casing bricks 1 or be mounted additionally thereon. Instead of the fastening blocks one can also use mechanical aids, e.g. metal profiles or other suitably formed fittings.

[0016] The fastening blocks or aids can also be located at any other suitable place on the inner surface of the casing bricks, e.g. in the corners of the casing bricks for receiving the outside corners of insulating elements formed into square frames according to Fig. 3.

[0017] The manner of fastening with fastening blocks 8 or the aid is advantageously used for all versions of insulating elements as in Figs. 4, 6 and 7. If this manner of fastening is used the abovementioned strong lining can be omitted.

[0018] The term "fastening block" is a simplified expression for an element which locks the insulating elements in the desired position but also positions the smoke tube column with insulating material in the center of the casing brick and holds it in this position.
In the embodiment of Fig. 8, chimney insulating element 3 is formed as a hexagon, with channel-like rear ventilation cavities 6 and 7 being formed between insulating element 3 and circular inner pipe 2, on the one hand, and between insulating element 3 and casing brick 1, on the other hand. In the shown embodiment, insulating element 3 is held on two opposite sides in the corner area by fastening blocks 8 with V-shaped receiving surfaces 9, whereas riblike projections 13 are formed on the two other sides of casing brick 1 for supporting the outside surfaces of insulating element 3 on both sides. Fastening blocks 8 and ribs 13 can here, too, be formed integrally with the casing brick or fastened to the casing brick as separate components.

Claims

1. A chimney insulating element of mineral wool for a three-layered, in particular ventilated, chimney with a flue gas- and waste gas-carrying inner pipe (2), the chimney insulating element (3) preferably of mineral wool disposed in tubular fashion around said pipe, and a casing (1) as a preformed part, characterized in that the chimney insulating element (3) forms a polygon at least with its outside contour.

2. The chimney insulating element of claim 1, characterized in that the inside contour of the chimney insulating element (3) forms a polygon corresponding to the outside contour.

3. The chimney insulating element of claim 1 or 2, characterized in that the outside and/or inside contour of the chimney insulating element (3) forms a pentagon, hexagon, heptagon but preferably a square or octagon.

4. The chimney insulating element of any of the above claims, characterized in that, with respect to the outside contour of the polygon, the length across the corners of the chimney insulating element (3) is greater than the clear width of the casing (1).

5. The chimney insulating element of any of the above claims, characterized in that the chimney insulating element (3) is in at least approximately linear contact with the outside of the inner pipe (2) so as to form ventilation channels (7) between inner pipe (2) and insulating element (3).

6. The chimney insulating element of claim 5, characterized in that the chimney insulating element (3) is partly in areal contact with a side of the casing (1).

7. The chimney insulating element of any of the above claims, characterized in that the chimney insulating element (3) is held within the casing (1) by force closure or with respect to the casing (1) and/or the inner pipe (2) by aids (8).

8. The chimney insulating element of claim 7, characterized in that the aids (8) engage the corners of the chimney insulating element (3) and are equipped with a V-shaped holding surface (9) in accordance with the corner contours of the insulating element (3).

9. The chimney insulating element of any of the above claims, characterized in that the chimney insulating element (3) is formed from one or more boards having V-shaped grooves parallel to their longitudinal axis designed in such a way as to permit the boards to be folded into a tubular chimney insulating element (3) with a polygonal contour.

10. The chimney insulating element of claim 9, characterized in that the board is preferably lined with glass mat or a strong surface material on the side facing away from the grooves (10).

11. The chimney insulating element of any of claims 8 to 10, characterized in that the surface of the board located between the grooves (10) is provided with a concave curvature (12) so as to conform with the inner pipe (2).

12. The chimney insulating element of any of the above claims, characterized in that continuous grooves forming additional ventilation channels (7) (Fig. 4) are provided in the chimney insulating element (3), being disposed preferably at uniform or regular intervals from one other.

Drawing